1. Technical Field
Embodiments of the present disclosure relate to integrated circuit devices and to command decoders.
2. Related Art
Mobile devices, including portable computers, personal digital assistants (PDAs), and cellular phones, may be reduced in weight in an effort to increase their portability. Batteries and semiconductor memory chips may be the important elements that directly influence the weight of a mobile. In the event that power consumption of the semiconductor memory chips (hereinafter, referred to as ‘mobile memory chips’) is lowered, capacity of the batteries can be reduced leading to a decrease in weight of the mobile devices. Accordingly, high performance mobile memory chips, for example, low power mobile memory chips have been continuously required to increase the portability of the mobile devices.
Mobile devices have been developed into multimedia devices providing various and diverse services. Thus, high performance mobile devices with fast operation speeds are required to support the multimedia devices. Data transmission speeds of the mobile memory chips may be an important factor that can directly influence the operation speeds of the mobile devices. Accordingly, a lot of efforts have been focused in on improvements of the data transmission speeds of the mobile memory chips.
Recently, low power double data rate 2 synchronous dynamic random access memory (LPDDR2 SDRAM; hereinafter, briefly referred to as ‘LPDDR2’) chips have been developed to significantly improve the power consumption and data transmission speed of the mobile devices. The LPDDR2 chips may exhibit the data transmission speed of about 8000 Mbps at a low power voltage of about 1.2 Volts. Further, the LPDDR2 chips may be fabricated using a process technology having a design rule of about 66 nanometers and may be encapsulated to have a planar package size of about 9×12 mm2.
The LPDDR2 chips may simultaneously receive command data and address data through 10 pins. That is, the signals received through the 10 pins include both command information and address information. A command decoder may decode the command data to generate command signals, and an address decoder may decode the address data to generate address signals.